Structural and Physiological Biology for Anatomy, Cell Biology and Physiology, Institute of Biology, University of Campinas (UNICAMP), 13083-862 Campinas, SP, Brazil.
Acta Histochem. 2012 Nov;114(7):665-72. doi: 10.1016/j.acthis.2011.12.001. Epub 2011 Dec 22.
The Malpighian tubule cell nuclei of male Panstrongylus megistus, a vector of Chagas disease, contain one chromocenter, which is composed solely of the Y chromosome. Considering that different chromosomes contribute to the composition of chromocenters in different triatomini species, the aim of this study was to determine the contribution of AT-, GC-, and methylated cytidine-rich DNA in the chromocenter as well as in euchromatin of Malpighian tubule cell nuclei of P. megistus in comparison with published data for Triatoma infestans. Staining with 4',6-diamidino-2-phenylindole/actinomycin D and chromomycin A(3)/distamycin, immunodetection of 5-methylcytidine and AgNOR test were used. The results revealed AT-rich/GC-poor DNA in the male chromocenter, but equally distributed AT and GC DNA sequences in male and female euchromatin, like in T. infestans. Accumulation of argyrophilic proteins encircling the chromocenter did not always correlate with that of GC-rich DNA. Methylated DNA identified by immunodetection was found sparsely distributed in the euchromatin of both sexes and at some points around the chromocenter edge, but it could not be considered responsible for chromatin condensation in the chromocenter, like in T. infestans. However, unlike in T. infestans, no correlation between the chromocenter AT-rich DNA and nucleolus organizing region (NOR) DNA was found in P. megistus.
班氏嗜木蜚蠊（Panstrongylus megistus），恰加斯病的传播媒介，其雄性个体的马尔皮基氏小管细胞核中含有一个染色体中心，该中心仅由 Y 染色体组成。考虑到不同的染色体在不同的三锥虫物种中参与染色体中心的组成，本研究的目的是确定在与发表的 Triatoma infestans 数据比较时，来自班氏嗜木蜚蠊的马尔皮基氏小管细胞核中的染色体中心和常染色质中 AT-、GC-和甲基化胞嘧啶丰富 DNA 的贡献。使用 4'，6-二脒基-2-苯吲哚/放线菌素 D 和 chromomycin A(3)/地高辛染色，免疫检测 5-甲基胞嘧啶和 AgNOR 试验。结果表明，雄性染色体中心中含有富含 AT/GC 贫乏的 DNA，但雄性和雌性常染色质中 AT 和 GC DNA 序列均匀分布，与 T. infestans 相似。围绕染色体中心积累的银染蛋白并不总是与富含 GC 的 DNA 相关。通过免疫检测发现的甲基化 DNA 在两性常染色质中稀疏分布，并且在染色体中心边缘的某些点周围也有分布，但不能认为其负责染色体中心的染色质浓缩，与 T. infestans 相似。然而，与 T. infestans 不同，在 P. megistus 中未发现染色体中心富含 AT 的 DNA 与核仁组织区（NOR）DNA 之间存在相关性。
